UA45326C2 - RADIO TELEPHONE SYSTEM (OPTIONS), METHOD OF OPERATION OF THE CLUSTER OF SUBSCRIBER LINEAR CIRCLES AND METHOD OF PROVIDING A REPEATED GROUP OF TEMPORARY MIRACLES - Google Patents

Abstract

A power-conserving time division multiple access (TDMA) radiotelephone system is disclosed in which a cluster of subscriber stations remote from a base station, employs a common pool of frequency-agile modems each of which digitally synthesizes, on a time slot-by-time slot basis, the different channel-identifying intermediate frequencies needed to support communications between several of the subscriber stations and the base station. Power conservation is facilitated inter alia by controlling the assignment of modems to calls, maintaining unassigned modems in a powered-down state and by controlling the number of calls using the same time slot Delay in assigning a powered-down modem to a call is eliminated by making available to all modems the highest quality synchronization information obtained by any of the active modems.

Description

Description of the invention

The invention relates to radiotelephone systems for serving multiple stations of remote 2 subscribers, more specifically, to radiotelephone systems in which some of those subscriber stations are located in close proximity to each other, i.e. in groups

A radiotelephone system containing a base station for servicing remote subscriber stations is described in US patent No. 5,119,375. In this system, each subscriber station is equipped with a radio station that receives commands from the base station to tune to a specific channel and 710. use a specific time interval during the duration of the conversation. Transmission over a radio channel with time compression was used for line communication from the base station to subscriber stations, and transmission with multistation access with time division (MDVR) of channels - for line communication from individual subscriber stations to the base station. Time division of each radio channel into time intervals and compression of speech signals allowed each radio frequency channel 72 to maintain the number of speech channels equal to the number of time intervals. The analog voice signal, entering the public switched telephone network and so on, was first converted into a digital sample of pulse-code modulation (PCM) with a transmission speed of b4kb/s. Before transmission on the radio channel, digital samples were subjected to speech compression to reduce the speed and transfer of speech information from b4kb/s to 14.bkb/s using finally excited coding with linear prediction. It was required that the speech codec and modem were specialized for a specific frequency! and time interval during the duration of the visa.

While the above-mentioned system worked quite satisfactorily, allowing telephone service to be provided, in particular, in areas where there is no wired connection, the unexpected growth of such telephone services has led to situations in which subscriber stations with 22 are located in close proximity to each other . Initial efforts to reduce the cost of Go) one line at the serviced group! such closely located subscriber stations were aimed at unifying the costs of installation and maintenance of individual subscriber stations due to the joint use of common equipment, such as a case, a power source, a power amplifier and an antenna.

Thus, in a group of closely located subscriber stations, each of which could have access to 30 RF channels, a single broadband RF power amplifier could be used to serve this group. However, it was still required that! each subscriber line had its own modem and radio transceiver. Exit signal! of individual transceivers were fed to a common RF power amplifier, which was supposed to provide control of the maximum power, equal to the sum of the powers of all transceivers in a group of adjacent subscriber stations, which could be 35 simultaneously active at the same time interval. It is obvious that it would be desirable to further increase the efficiency compared to the result provided by patent 5 119 375, to reduce the maximum and average required power, especially in remote areas requiring service using the power of solar cells. "

According to the principles of the invention, communication line costs are reduced for physically compact groups! With 70 subscriber lines by means of provision for lines within such groups! not only from the common source of energy and from the RF power amplifier, but also from the common modem, synchronization, intermediate frequency! (IF), conversion functions with increasing and decreasing the frequency of the controller, so that a significant concentration of resources is achieved. In such a system, a small number of modems are provided to serve numerous subscribers in a physically close group, called a cluster or, more specifically, a 45-module cluster. In an illustrative version, the subscriber circuits and the modem are a modular printed circuit board that is inserted into a switching board that uses a common circuit board to distribute information about time characteristics and data between blocks. Any of the modems can be used to control visas for several subscribers at consecutive time intervals. ka 20 A feature of the invention is that the selection from the common pool of modems with fast modem frequency adjustment for visa management is regulated to save power consumption in two ways. First of all, the new modem is preferably not used for visa processing until the interval is complete! there will be no classes on active modems! by visas, which allows all modems that have not yet been activated to remain in a power-saving "reduced power" state.

Secondly, the number of visas using the same time interval (at different frequencies),

HF) is adjusted to reduce the maximum power consumption of the RF power amplifier.

The next feature of the invention is the exclusion of the synchronization delay when it is necessary to use a modem in a state of reduced power for applying it to a visa. As soon as the synchronization of the time interval with the base station is established for the first modem of that pool at 60 given cluster (group), information about the synchronization becomes available to the rest of the modems, mainly through the unifying board, under the control of the microprocessor-based cluster controller. That's why everything is a modem! with reduced power are immediately made available without any delay to obtain synchronization with the time division cycle of the base station.

The next feature of the invention is the classification of modem synchronization states in accordance with several classification parameters and obtaining a confidence level (confidence probability) for each active modem, reflecting the reliability of the synchronization parameters, and the distribution of synchronization information from the modem with the best confidence level.

The preceding and other objects and features of the invention will be more apparent from the following description, illustrated by the drawings, in which the following are presented:

Fig. 1 - block diagram of a modular cluster having a common pool of modems with fast frequency adjustment for processing a group of subscriber points;

Fig. 2A - illustration of the connection of subscriber line circuits and modems in time slot exchange equipment; 70 Fig. 28 - RF cycle of multi-station access with time division (MDVR) of channels, allocated for time intervals of 16-position phase manipulation;

Fig. 2C - Rch-cycle MDVR, allocated for time intervals of quadrature phase manipulation;

Fig. 20 - distribution of tasks between time intervals of MDVR and PCM buffers;

Fig. With - zlement!i principle schemes! modem module with fast frequency adjustment;

Fig. 4 - block of intermediate frequency (IF) of the modem with fast frequency adjustment;

Fig. 5 - block diagram of the synthesizer block of the frequency increase/decrease converter;

Fig. 6 - frequency synthesizer and noise generator for the receiving part of the modem;

Fig. 7 - scheme, frequency synthesis, modulation and noise generator at an intermediate frequency for the transmitting part of the modem;

Fig. 8 - the scheme of generating synchronous pulses for a modular cluster.

In fig. 1 presents a block diagram of a modular subscriber cluster remote from the base station (not shown). The subscriber cluster is called "modular" because there are 100 linear circuits and a modem! 400 consist of removable blocks. Therefore, the number of replaceable subscriber line circuits 100 will depend on the number of subscribers in this area, and the number of replaceable modems 400 can be selected taking into account the processing of the workload expected from this number of line circuits 100. Line circuits 100 are contained on four linear modular printing boards 101 - 108, each of which serves four subscriber lines. and)

Eight such quadrilateral linear modules provide functions of closed systems! automatic control of a group of 32 subscriber lines, and circuits 100 can contain multiple line groups.

Each linear circuit on each quadrilateral linear module 101 - 108 causes the appearance of Ges from a specialized time interval of pulse code modulation (PCM) in the PCM path of speech signal transmission 200 and in the visual (signaling) path 201. Modules 101 - 108 include codecs of speech signals (not readings) for encoding the analog voice signal of the subscriber circuit for transmission in the path (with 200 PCM-data. Signaling information for the subscriber circuit is fed into the signaling path 201 by means of the subscriber line interface circuits. Coding according to the law of

M-compounding or according to the law of A-compounding. "Mr

The connection of a specific one of the modems 400 for visa processing from one specific chain of linear chains or to one specific chain of linear chains with one of the four linear modules 101 - 108 is made through the blocks of exchange of time intervals 310 and 320 at the command of the cluster controller 300. The exchange block 320 time slots PCM of data transmits voice samples between "MKM-path of speech signal transmission 200, serving linear modules 101 - 108, and MYKM-path of voice signal transmission 220, serving the pool of modems 400. Exchange block 310 time intervals. The Vizova transmits the Vizova information between the Vizova tract 201, which serves modules 100, and the U? visa 221, serving a pool of 400 modems.

Needed for a phone call! two RF channels, one for transmission from the base station to the subscriber

"Forward" channel) and one from the subscriber to the base station ("reverse" channel). in the cluster from the base station, it can be traced from the cluster antenna 900 and the antenna switch 800 to the synthesizer block and the frequency up- and down-converter 600.

In the converter unit 600, the RF signal is limited, filtered into a frequency band, converted with a decrease in frequency from the RF signal band to a frequency of 45 MHz, 900 MHz or another high or super high frequency

F frequency! in the intermediate frequency signal! (IF) in the range of 26 - 28 MHz. The IF signal is fed to the modems 400, which process the signal to be fed to the subscriber's line circuits through the blocks of exchange of time intervals in the cluster controller 300. 5B Each of the modems includes a digital signal processor! frequencies of modulating signals (see Fig. C, O5R/BB) and the modem processor (see Fig. C, O5R/MOM). In the directional transmission of the direct channel

F) the OZR/MOM modem processor demodulates the IF signal received from the converter block 600 and transmits this data to the digital signal processor O5R/BB, which converts the demodulated data into coded according to the M-law or d-law of signal compounding for transmission through block 320 for the exchange of time intervals to linear modules. The processor of the digital signal OZR/VV of the modem is connected to the processor of the OZR/MOM modem through the interface of direct access to the memory (see Fig. 3, OMA) and with the paths of the PCM through the serial port of the processor. In the direction of transmission in the reverse channel, the digital signal processor О5Р/ВВ converts the information encoded according to the M-law or according to the A-law of PCM compounding, received from the PCM tract 500, into a linear form, compresses this linear data with the help of finally 65 excited coding with linear prediction (KEG R) and transmits the compressed data with the help of OMA to the digital signal processor UOZR/MOM, which modulates this signal for transmission in the time interval of the radio channel.

As shown in Fig. 2A, each of the modems 400 and each of the line modules 100 has four specialized types of time slots in the exchange block of 320 computer data time slots for non-blocking access. Each modem is intended for two adjacent PCM intervals in PCM time intervals 0 - 15 and for two adjacent PCM time intervals in PCM time intervals 16 - 31.

For example, for a specific visa, the time slot exchanger T51 320 connects linear circuit 0 of linear module 101 with channel 1 of modem 1 and linear circuit 1 of linear module 101 with channel 0 of modem 1, etc. Time slot exchange blocks 310 and 320 provide a repeating sampling period of 7/0 with a duration of 125 μs, consisting of 32 time slots, at a data transfer rate of 2.048 Mb/s. During each 125μs PCM interval, the line modules can send 32 8-bit bytes of data to the time slot exchange unit 320, and each modem can receive 4 8-bit bytes on its serial port of the group signal processor, packed together as two 16-bit words

Each 16-bit word carries an interrupt signal on the serial port of the group /5 signal processor. Upon receiving an interrupt signal, the group signal processor determines whether the pair matches

of PCM samples contained in that 16-bit word, intervals 0 and 1 or intervals 2 and 3. Similarly, during each PCM interval of 125 μs, four speech channels of PCM data, packed together in the form of two 16-bit words, can beat messages from the serial port of each group signal processor to the time slot exchange unit 320 for delivery to the line modules.

The RF cycle of time compression at the base station is shown in Fig. 2V and 2C, with a duration of 45ms each. Cycle 16b-position FMn, Fig. 28 has four time intervals, each with a duration of "x", and each time interval is capable of carrying a different frequency provided to the forward and reverse channels of the visa. In Fig. A 2C RF cycle of the same duration ensures the implementation of the forward and reverse channels of two VISs modulated by means of quadrature FM. It is clear from 285 that the time compression scheme can ensure the transmission of four visas with a 16-position FMn. or two views with quadrature FMNn. and)

Fig. 20 illustrate the synchronization of tasks performed in the cluster during the transfer of information between the considered MDVR scheme with the use of images modulated by quadrature FM

PCM tracts. Line (1) represents a buffer for receiving two modulated quadrature FMn Ge) time intervals of the direct channel, KXiI and Kx2, of the MDVR cycle. Demodulation begins as soon as the buffer receives the first half, XXia, of the time interval. Line (2) represents the buffer, ready for transmission in two modulated quadrature FMn time intervals of the reverse channel Th! and Th2, MDVR cycle. "co

Note that in the cluster, the time intervals of the reverse channel are offset relative to the time intervals of the forward channel, so that the costs of the antenna switch can be avoided. In addition, the reverse channel of the subscriber unit is shifted in such a way that it will be received at the base station at the appropriate time, taking into account the distance between the subscriber point and the base station. Lines (3) and (4) in Fig. 20 means buffer! in the static RAM (Fig. 3) of the modem, which stores PCM words during transmission to the exchange unit T51, 320 speech time intervals and from it (Fig. 1). "

In normal speech mode, the OZBR/MDM modem processor demodulates the received symbol! direct channel, packs them into a buffer in the static buffer of the ZKAM/MOM modem (Fig. 3) and sends the contents of that buffer to the OZR/BB group signal processor for KEI P-synthesis (expansion). The processor of the group signal encodes the extended data according to the M-characteristic or the A-characteristic and transmits it to the "» bus of the PCM data for delivery to the linear modules. The code words of the speech signals are transmitted in each cycle during the active speech mode. The code word is located at the beginning of the packet of data between the header and the speech data in both the forward and reverse channels. The code words of the speech signals of the forward channel and contain information that can be used to adjust the transmission power and synchronization. c Information of the local subscriber circuit (ie, subscriber response, of the subscriber, visa, disconnection of the direct channel) can also be entered into the code word. The code words of the reverse channel contain (95) information about the local subscriber circuit and the quality of the direct channel connection. 50 The code word of the direct channel voice signal is decoded by the modem processor /MOM) Because the code word contains information about the adjustment of the transmitted fractional synchronization operation, adjustment 42) of the transmitted power level and adjustment of the local circuit. Information about fractional synchronization and power level adjustment is averaged during the cycle, and the averaged adjustment is performed at the end of the cycle. Local chain management information is stored locally, and changes in the state of the chain are detected and communicated to the cluster controller. Control of the local circuit also causes the modem to transmit the control signal of the line circuit on the signaling bus. The code word of the speech signal of the reverse channel includes the status of the local circuit, which is used by the cluster controller and the base station to control the passage of the visa.

The processor of the O5R/MOM modem performs filtering with a finite impulse response and automatic adjustment of the gain of received signals in the service program with the interruption of received symbols.

The demodulator program in the modem processor is activated when half of the information time interval of the group spectrum of the transmitted signals is received in the receiving buffer. The demodulator works for half the data interval and transmits the packed output data to the group signal processor

О5Р/ВВ for KEGR synthesis. The transfer of data to the group signal processor and from it is regulated in such a way that the input queues of the KEY R are filled before the corresponding synthesis data is needed, and the output queues of the KEYR are emptied before the output data of the new analysis (compression) arrives. Automatic frequency adjustment takes place during demodulation! (ARC), automatic gain control (ACU) and bit tracking processors to maintain accurate synchronization with the base station.

It is clear that a mixed mode of operation is possible, with a certain time interval! they can

Use 16-position FM modulation, while the rest is an interval! can use quadrature PMNn modulation.

Synchronization with the base station

Before using the RF channel for communication between the base station and the cluster, the cluster must be synchronized with the cycle of RU time intervals used by the base station (not shown). According to the invention, one or more modems 400 receive a command from the cluster controller Z00 to synchronize with the cyclic synchronization of the RU-base station by searching for the frequency of the channel carrying the radio control channel used by the base station. The cluster controller 300 includes a central control microprocessor 330, such as the Moiogoia 68000 series processor, which sends control information via the SR (CPU) bus to the microprocessors in the 7/5 3200 modems. When power is applied, the cluster controller 300 loads the appropriate software data and the initial data to the modem 400. After finding the frequency of the channel, the modem must synchronize with the time interval of the base station by decoding a unique word (radio channel of KSS control). As described in the above-mentioned patent 5 119 375, the KSS channel differs from other channels in that it has an extended guard interval in its time interval and includes an OVROZK modulated unique word of 8 bits. To reduce the possibility of canceling a call, if there is no modem with an active KSS time slot and it becomes necessary to provide the KSS time slot to the second modem, then the time slot! are provided inside the active modem in such a way that the synchronization time interval (KSS) (called KxHO, where the four time intervals are XO - KHZ, or KX1, where the four time intervals are KXII - KX4) is the last one that must be filled.

When starting, it is assumed that everything is a modem! 400 out of sync! with a base station RF cycle of 45ms. and)

During the time interval 0 of that RF cycle, the base station transmits the KSS message on some

of the RF channel, which when received in the modular cluster, will be decoded, synchronizing the cluster with

RF cycle time slots of the base station for all RFC channels. Until synchronization with the base station is achieved, each modem generates its own local RF cycle synchronization. Then the cluster controller 300 commands one or more modems to search CSC transmitted by the base station on different RF channels until CSC is found or all channels are searched. If after searching all channels CSC is not found, the controller gives the command to start searching again When one of the modems finds a KSS (radio channel of control), the controller designates it as a KSS modem and distributes its synchronization information to all other modems through a cyclic synchronization signal using the unifying board.

When searching for the CCS interval, the channel number is used by the modem for digital tuning of the local oscillator frequency of direct digital synthesis of frequencies! (0OE5), for example, in the range of 2 MHz. There are two stages for capturing the KSS channel by the modem: rough detection of the frequency of the communication channel and finding the "AM-hole", a part of the KSS time channel, in which the number of symbols transmitted by the base station does not fill the entire 7-3) s time interval. Coarse frequency capture is based on the Hilbert transform of the spectrum

And the KsSs channel, which gives frequency correction! for local oscillator. This continues until the energy in the upper half of the spectrum approaches the energy in the lower half.

After a rough capture of the frequency, for example, with an accuracy of 300 Hz relative to the frequency of the communication channel, an AM hole is searched for. A series of zero signals is transmitted before the KSS data, the AM-hole and 5" is detected by controlling the amplitude of successively received symbols. Upon detection of 12 consecutive zero symbols, the modem outputs an AM strobe signal indicating the beginning of the KSS interval and the beginning of the MDVR cycle. That roughly synchronizes the temporal characteristics of the modem band of modulating frequencies with the temporal characteristics of the base station. Synchronization must be performed only once, since the radio channel is common to all modems of the modulating signal band in the modular cluster. o The cyclic synchronization signal is transmitted by one modem to all other modems in the cluster via

Ф of the signal transmitted over conductors on the connecting board. When searching for KSS, if an AM-hole is found within up to 3-symbol periods from the beginning of the cyclic marker, the coarse capture is completed.

The detection of a unique word within the cycle provides the modem with synchronization information, which is used to synchronize the local timing of the modem to the nearest 1 symbol with the base station. The modem is in a state of synchronization when receiving Kx DSS, as long as it continues to receive and decode the correct unique word. Once synchronization is achieved, 16b6-position FMn modulation corresponding to 4 bits per symbol, quadrature modulation, can be applied. corresponding to 2 bits per symbol, or combinations thereof. Although all modems are capable of receiving the radio control signal (RCS) of the base station and synchronizing with it, only one modem must do so, since the modem selected by the cluster controller can use synchronization together with other modems by means of a cyclic synchronization signal with the help of the unifying board.

When connecting the modem to the central processor, the O5BR/MOM modem processor transmits the command to

ОО 450 (Fig. 3) will try to synchronize the local cyclic timing with the signal of the unifying board. Chronirovanie OO 450 of each modem at this moment regardless of the hronirovanie of each second modem. First, the SOR 450 unit receives a command from its UO5R/MOM processor to search for a signal

Unifying board for synchronization. If the synchronization signal of the unifying board is present, the BOR will synchronize its cyclic synchronization signal with the signal of the unifying board), and then disconnect from the signal of the unifying board. Thus, the signal of the unifying board is not fed directly to the modem timing scheme, but only combines the internal start of the modem with the reception of the cycle signal. If the synchronization signal is unified pay! /o is absent, then it is assumed that this modem is first activated by the cluster controller, and in this case the cluster controller 300 gives a command to the OZR/MOM modem processor to search for the KSS and transmits a message about the modem's timing to the cluster controller.

Then the cluster controller 300 commands the O5R/MOM modem processor to demodulate

OVRBZK signal in the KSS channel. The demodulation channel of the IF signal received from the converter 600 can /5 pass to the IF-modem module, where it is again filtered by a band-pass filter and converted with a decrease in frequency with the formation of an information stream at a speed of 16 kilosymbols per second. OVROK modulation used in the KSS channel is a modulation of the type one bit per symbol. Signal!

KSS, accept from the base station, you must! beat demodulation and decoding! before sending them to the cluster controller. Only messages (signal!), which addressing! to the cluster controller, have 2 o permissible SCS (control with a cyclic redundant code) and are recognized as packet-type signals or confirmation signals, sent to the controller. All other messages are discarded. The confirmation signal means the correct reception of the previous CCS signal. The signal is addressed to the cluster controller if the subscriber identification number (SIN) contained in the message matches

SIU of that cluster. high school

According to Fig. From the IF signal with a speed of 16 kilosymbols per second from the IF circuit (Fig. 4) enters the analog-to-digital converter 804, in which sampling is performed at a speed of 64 kHz with i) the help of a sync signal received from the OOE 450 block. The analog-to-digital converter 804 produces quadrature discretization in the bandwidth with a sampling frequency of 4kHz. Quadrature discretization in the passband is described, for example, in US patent No. 4,764,940. At the input of the converter 804, a sequence of complex signals is formed, which has some temporal distortion. The input signal of the converter 804 (Fig. 8) enters the stack of received signals with (EXHRIRO) in the OOE 450 block. The OBR/MOM modem processor reads the contents of the KHRIIRO block and performs a complex filtering operation with a finite impulse response, which removes the temporal distortion introduced by the quadrature discretization in the bandwidth. After removing the temporary o

Зз5 distorted signal! are demodulated by the OBR/MOM processor. "IS

During the demodulation of signals, the KSS processor of the YuO5ZR/MOM modem performs automatic frequency tuning, automatic gain adjustment, and bit tracking to maintain the exact synchronization of the cluster with the base station. Adjustments of transmission time and power level are made in accordance with the information contained in the received KSS signal. The OBR/MOM processor analyzes the demodulated "0" data and detects the CCS signal, which includes a beat! state of the communication channel, and data of 96 bits, which include the subscriber identification number (SIN). The O5P/MOM modem processor also recognizes whether the ZIO belongs to one of the subscriber line circuits in that cluster. ;" If the received message is a message for that cluster, it is transmitted to the cluster controller 300, which interprets the KSO command. Direct messages of the KSS include the message of a visa search, establishing a connection for a visa, specifying a free line and self-checking. Return and 5" KSS messages include receiving a visa, a request for a free line, the result! checks and visa application. If the KSS message is a search visa message, then the cluster controller for which this message is intended will generate a message about receiving a visa for transmission back to the base station. From the reception message, the base station determines the time difference between the cluster and the base station, after which the base station sends symbolic information about synchronization correction to the cluster in the next KSS message, which is a message about the established connection

F for a visa.

If the KSS message is a message about an established visa connection, then the information contained in it is a command for the cluster controller about what adjustment to make in the symbol synchronization, whether it is necessary to adjust the power level, fractional timing, and what channel to use for the rest of the visa (number channel, number of the time interval (F, time compression, whether quadrature FMn or 16-position FMn modulation will be used and what is the type of subscriber line).

The first modem that detects a KSS is designated as a KSS modem, and its frequency shift, gain adjustment, and information about the start of the cycle are considered correct and can be extended to other modems.

The cluster controller receives information about the number of that channel and decides which modem should receive the command to set to that channel to process the rest of the visa.

The final stage in achieving general synchronization is the successful installation of the voice channel. When the voice channel is established, the last two synchronization parameters become correct: 65 synchronization of transmitted symbols and fractional synchronization of transmitted symbols. At that moment, when the cluster controller activates the second modem, all the necessary information about synchronization is available to provide it to the second modem, which facilitates and speeds up the installation of the voice channel. The confidence level (confidence probability) is calculated to estimate the synchronization information of each modem. The cluster controller adjusts the trust level for each modem as soon as there is a change in the state of synchronization, the quality of the connection or the AGC during reception. The cluster controller finds the modem with the highest trust level and distributes its synchronization parameter to the rest of the modem!.

When the modem receives a command from the cluster controller to enter speech mode, the modem first tries to perform cleaning. Cleaning is a process of exact synchronization 7/0 Modem transmission timing and power level with base station reception timing. The cleaning process is regulated by the base station. The base station and the modem exchange special cleaning packets until the base station completes the cleaning process upon reaching the specified degree of synchronization. Then the modem switches to normal voice mode. If the base station stops the cleaning process, the modem will stop viewing, go into silent mode and inform the cluster 7/5 Controller. Cleaning packages are OVRZK packages, formatted similarly to KSS packages. The cleaning package is detected by the presence of a unique cleaning word. A modem is considered to be in voice synchronization when a unique clearing word is detected with a zero offset. Code words of speech signals of direct and reverse communication have a control byte of the code word of speech signals, added for error detection. The modem will report loss of synchronization if 9 2 consecutive cycles are received with voice code word errors. In this case, the cluster controller enters recovery mode and remains in recovery mode until a good code word is detected, or until the modem receives a command to exit recovery mode and enter silent mode.

Based on the state of synchronization, the cluster controller 300 determines the correctness of the synchronization parameters provided by that modem. The table below shows which parameter! are recognized as correct, based on the current state of modem synchronization. "X" in the table indicates that this parameter is correct.

Ooobynkhrootuttvut 010111 so zro banquetvymaso 000X000011x oh

Synchronized broadcasts 00050010 x x m s

The 12-bit confidence level word is calculated by the modem to reflect the reliability of the IF) synchronization parameters set by the modem. The word of the trust level is made by the concatenation of bits "representing the state of speech synchronization and modem reception, with bits identifying the communication quality parameter and the received AGC, as presented in the following table. espredelenis biyue| 10111110917098,; 79 « - s Single bits 11 and 10 show, respectively, whether the modem is or is not in "" speech and reception synchronization. Two bits 9 and 8 identify 4 gradations of communication quality, while 8 bits "are intended for obtaining the level of automatic adjustment amplification, indicate the required level of amplification.

Modem module, Fig. The main components of the modem module are shown in Fig. 3. This module can support up to 4 h simultaneous duplex voice channels. Processing for dynamic manipulation of all functions required by the active channel is divided between the processor of the cluster controller 320 (Fig. 1) and the processors Y5BR/MOM (modem processor) and O5R/VV (group signal processor) in each

GI 20 modem (Fig. 3). The O5R/MOM modem processor provides filtering, demodulation, and routing of incoming radio signals, data formatting before transmission over the radio channel, and control of the m, data flow between it and the Yu5R/VV group processor. The YuO5R/VV group signal processor performs computationally intensive tasks of speech compression and expansion and, in addition, serves the PCM-bus connection. In normal speech mode, the OZR/MOM modem processor demodulates received symbols, packs them into the receiving buffer and sends the buffer with speech data to the group processor

F! О5Р/ВВ for KEI P-synthesis and transmission to the subscriber's line circuit through the computer bus. Modem processor

OBR/MOM also accepts compressed speech from the О5Р/ВВ group signal processor and formats it into a packet! about the MDVR and sends to the filter for the formation of transmitted pulses, contained in SOE 450, for transmission over the radio channel. This modem works with both quadrature FM modulation and FM modulation signals (and 60 bursts during cleaning) under the control of the cluster controller.

Each of the O5R/VV and O5R/MOM processors has a specialized static ZUPV, 5 VAM/MOM and

ZKAM/VV, respectively. However, the O5R/MOM modem processor may request access to the static

ZUPV 5KAM/VV by activating its output engages direct access to memory (OMA) and receives such access with the help of data buses and address buses! upon activation by the processor of the OZR/BB group signal of its output 62 signal of the confirmation symbol of direct access to the memory (OMAASK).

Distribution of time intervals

As described in patent 5 119 375, the switchgear in the base station stores the trajectory of the radio signals and the time interval that are used, and distributes both the frequency and the time interval! for use at every vyzove. Choose the interval that is used by the smallest number of visas in such a way that the visa load could be more evenly distributed over all intervals. However, in accordance with the aspect of this invention, which concerns the reduction of power consumed in a remote modular cluster, visas are provided in such a way that a) reduce the number of active modems and b) regulate the number of conversations that simultaneously use the same time interval!. Further, although 7/0, it is desirable to apply modulation using 16b-position FMn in each time interval

MDVER of the cycle, so that it was possible to coordinate four full visas, it is also important to ensure the establishment of visas using quadrature FMn and preserve the alternating KSsS-interval, suitable for the purposes of synchronization. Therefore, the cluster and the base station must! to cooperate at the allocated time intervals to achieve those goals. The cluster keeps track of the available time slot and the type of /5 Modulation used in each slot. Then the cluster prescribes priority levels for each available interval and maintains a matrix of priority values, which teaches that a) the next reception time interval (as a rule, the first time interval) on a certain channel should be designated for CCC synchronization, b) adjacent time intervals interval! duty! remain available as long as possible, so that, if necessary, it is possible to distribute ORZK visas, and c) a time interval! duty! the battle of submissions! for processing visas, if possible, without activating a modem with reduced power or without providing an interval that is already used by a large number of other visas.

The program (in pseudocode) for achieving these goals is as follows:

The program for determining the priority of time intervals

List 1 - all free time slots available on active modems for 16P5K calls and ЧРЗК calls;

List 1A - all free modems; (8)

List 2 - List of time intervals, the use of which will not exceed the threshold number of visas using the same time interval in that cluster;

List 2A - List 1 minus List 2; Gezo List C - List 2 minus the time interval! on modems that have nearby available (for visas

ORBZK) time intervals; with

List ZA - List 2 minus the time interval on modems that do not have adjacent available (for ORZK (and video) time intervals;

List 4 - List C minus the time interval! on modems that do not have an available for synchronization o

335 Time interval (interval 0 for KSS); "IS

List 4A - List 4 minus the time interval! on modems that have an available time interval for synchronization;

Mark list 4 as the first choice;

Mark list 4A as the second vibor; "

Mark the list With as the third vibration; в с Mark the ZA list as the fourth option;

Mark list 2 as the fifth option; with Mark list 2A as the sixth vibor;

Mark list 1 as the seventh choice;

Mark list 1A as the eighth option. и5» The described interval prioritization program is called as soon as the cluster receives the KSS signal of the search visa from the base station, when the cluster gathers to send the visa request signal to the base station. When the base station responds with a message about the enabled visa, containing the frequency, type of modulation and the time interval that should be used, the cluster once again executes the priority determination program to find out whether the selected CRO-interval is still available. If it is still available, it is granted for this visa. However, if meanwhile the distribution of intervals

F have changed, the visa may be blocked.

An example of how the priority determination program is implemented under light and heavy load conditions may be useful. Let's first consider the following table, which illustrates the possible state of modems and assigned time intervals under light load conditions, just before one of the subscribers served by this modular cluster initiates a service request: axles

SavRvk 00 orvkoorvk r 41715 v5 ni o po PO

The above table shows that modem 0 has available slots 2 and 3, modem 1 has available slots 1 and 2! 2, C, 4 and 5 have reduced power, and all their time interval! are recognized as freedoms. The cluster executes the program for determining the priority of intervals, which determines that intervals 1, 2 and Z, in this sequence, are the preferred intervals for providing the next 16 RZK visas for processing, and that for ORZK visas, the preferred intervals are 2 and 0, in this sequence. Then the cluster sends the "visa request" signal to the base station using the KSS word and informs the base station about this preference. The table below presents the logical basis for each of the priorities: interval 16Р5К interval ORZK activity interval; ORZK-interval! 2, C remain available; case 16 RZK for

KSSo-interval is available. intervals 2, 3)

Fri Mon Thu Fri from the new modem 11111111 I requested the connection of the new modem|.//./: NOI

A second example might be useful. Let's consider the state of the time intervals among modems 0 - 5 under somewhat heavier load conditions, as shown in the following table, where the cells indicate the free time interval! !) sch

The provision of time intervals is shown in the following table together with logical reasons: со 2 intervals 16Р5К interval ORZK " and

ORZK-interval 2, Z remain available; The KSS interval remains available until the LEENyunmenyany 00

KSS-interval is available; MO new ORZK-viizov requires increasing the power of the new "modem;

PI PD vn nn NIC NI Kn are available, but max, the interval activity is exceeded 5 SP-chales AND 1 z» is exceeded, and the KSS-interval is not available

Up/down converter 600

As shown in Fig. 5, the radio signal of the direct channel from the base station is received in an up/down converter 600 by means of an antenna switch 800. The received RF signal passes through a low-noise amplifier 502, is filtered by a band-pass filter 503, is attenuated in an attenuator 504, and is fed to frequency converter! 505, where it undergoes the first down-conversion from the 450 MHz RU-band or 900 MHz RU"-band to an IF signal in the range of 26 - 28 MHz. The IF signal passes through an amplifier 506, a band-pass filter 507, an amplifier 508 and an attenuator 509 and is fed to the splitter 510 for delivery to the entire pool of modems. 4" The modulated IF - signal of the reverse channel from the entire pool of modems is fed to the combiner of the up/down converter 600 in the upper left corner of Fig. 5, is attenuated in the attenuator 521, filtered in the bandpass filter 522, are amplified in the amplifier 523 and fed to the frequency converter 525, where the signal is converted with a frequency increase into an RF signal or an RF band

Gee! 450 MHz, or in the RUCH band 900 MHz. Then the RF signal is attenuated in the attenuator 526, filtered in the bandpass filter 527, amplified in the amplifier 528 and fed to the broadband amplifier 700 of high power, which sends this signal to the antenna switch 800.

Frequency converters 505 and 525 receive their reference frequency from the phase automatic frequency adjustment system 60 (PLL) 540 during reception and the PLL system 550 during transmission, respectively. System

PLL 540 generates a local oscillator signal of the receiver at a frequency of 1.36 MHz from the signal amplified by the set clock generator 560 frequencies! 21.76 MHz, dividing by 2 and then by 8. Signal frequency! 1.36 MHz provides the reference input signal for the RS phase comparator. The second input signal of the phase comparator is provided by a feedback circuit that divides the output signal of the circuit 540 by 2 and then by 65 177. The reverse supply of that signal to the phase comparator causes the output signal of the circuit 540 to have a frequency that is 354 times greater! reference signal, i.e. 481.44 MHz. Input signal frequency

481.44 MHz of the PLL system 540 when received is fed as a local oscillator input signal to the down-frequency converter 505.

Input signal frequency! 481.44 MHz of circuit 540 is also provided as a reference input signal for circuit 550, so that circuit 550 is frequency-corrected with circuit 540. Circuit 550 generates a transmitted local oscillator signal, which has a frequency of 481.44 MHz and 5.44 MHz, i.e. it has a frequency that is shifted upwards by 5.44 MHz compared to the received local oscillator signal. For the circuit 550, the 21.76 MHz signal from the generator of the main synchronous pulses 560 is divided by 2, then again by 2 with the formation of a signal with a frequency of 5.44 MHz, which is fed to the input of the reference signal of the phase comparator of the RS-circuit 550. The second input signal of the phase 7/0 Comparator RS-circuit 550 is the difference frequency filtered by means of a low-pass filter (LFF) between the received local oscillator signal from the circuit 540 and the output signal of the voltage-controlled generator (VCO) of the circuit 550. The output signal of the circuit 550 is from the output of its internal voltage-controlled generator (VCO , HUN), is a frequency of 481.44 MHz and 544 MHz.

Fig. 4, IF part of the modem

In Fig. 4 shows the IF part of the board in detail! modem relative to digital parts (Fig. 3). As shown in the lower right side of Fig. 4, the received IF signal from the VBOI 600 (Fig. 1) is fed through the lower output of the reverse circuit switch 402 to the 4-band bandpass filter 404, with a band from 26 to 28.3 MHz. Then the output signal of the filter 404 is amplified by the amplifier 406 and transformed with a decrease in frequency! in the converter 408, which uses the received local oscillator signal, having a frequency in the interval from 15.1MHz 2o to 174MHz. The output signal of the converter 408 is amplified by the amplifier 410 and filtered by means of an 8-band quartz filter 412 with a central frequency of 10.864 MHz. The amplitude of the signal at the output of the filter 412 is regulated by the AGC circuit 414. The gain of the AGC circuit 414 is regulated by the MASS signal from OB ABIS (specialized IC) 450 (Fig. 3). The input signal of the AGC circuit 414 is then converted to a step-down converter 416 using a reference frequency of 10.88 MHz. As a result, a sequence of IF data is formed, transmitted at a speed of 16 kilosymbols/s, which passes through the amplifier 418 and enters the receiving input port of the IF circuit! according to Fig. 3. i)

The scheme presented in Fig. C, generates a local oscillator signal KxH.O.OE5, which is filtered by a 7-band filter 432, then amplified by an amplifier 434. The output signal of the amplifier 434 is again filtered by a low-pass filter 436, the output signal of which is amplified by an amplifier 438 and then mixed with the resulting IF- radio signal to mixer 408.

As shown in the right part of Fig. 4, the amplifier 420 receives the signal of the master generator with a frequency of 21.76 MHz and feeds it to the splitter 422. One output signal of the splitter 422 is doubled in frequency with a frequency doubler! 424, the output signal of which is limited in the limiter 426 and converted to the level of transistor-transistor logic circuits by the logic element 428 and inverted again by

C5 Logic element 430. The output signal of the logic element 430 is fed to the circuit in Figs. With the quality of "E reference synchronization signal frequency! 43.52 MHz.

The second output signal of the splitter 422 passes through the amplifier 454 and the attenuator 456 and is fed to the heterodyne input (I) of the mixer 444. The mixer 444 converts with an increase in the frequency of the modulated

IF-signal Tx O 1E with schemes! according to Fig. After it is filtered in a low-pass filter 440 and attenuated by an attenuator 422. The output of the logic element 428 is also connected to the input of the inverter 460, the frequency of the output signal of which is divided by 4 by a frequency divider 462 and then used as a local oscillator for frequency reduction ! of the output signal of the AGC unit 414 in the mixer 416.

The reverse circuit function is provided by a series combination of switches 450 and 402 and an absorbing load 458, so that the signal! from the output of the Tx GRAY scheme in Fig. They can be fed back to the 5" input of Ex 1E for verification purposes when submitting test sequences to compensate for distorted signals, for example, in a quartz filter 412. 1 Scheme according to Fig. C provides a modulated IF input signal with a frequency of 4.64 - 6.94MHz, which 2) is filtered by a 7-pole filter 440 and attenuated by an attenuator 442. The output signal of the attenuator 442 is fed to the mixer (frequency converter) 444, where it is transformed with a frequency increase! to a frequency in the range of 26.4 MHz - 28.7 MHz. The input signal of the frequency converter 444 goes to

F amplifier 446, the output signal of which is filtered by a 4-band band-pass filter 448 and is fed to the switch 450, which is controlled by the output signal of the I VE activation of the reverse circuit with circuits! on

Fig. 3. When the test is carried out, the output of the I VE is filled by connecting the switch 450 to the input of the filter 448 with the upper part of the absorbing load 458 and connecting the switch 402 to connect the lower part of the absorbing load 358 with the bandpass filter 404 for testing with (F, using the reverse circuit. testing is carried out using test sequences to compensate for distorted signals in the quartz filter 412 and in other modem circuits.

If testing with the use of the reverse circuit is not carried out, the output of the switch 450 is connected to the programmable attenuator 452, which can be programmed to one of 16 different levels of attenuation by the signal for adjusting the level of the transmitted power, Tx RI C, from the diagrams! according to Fig. 3.

The input signal of the attenuator 452 contains Tx 1 ROKT signal, which is fed to the upper left side (Fig. 5).

Fig. 6, ECHO - Generation of a digital intermediate signal for reception channels 65 The exact intermediate frequency for setting during the reception time interval is determined when the SS cluster controller (Fig. 1) informs the modem in which RF channel to search

CCS signal. "Since the reception of the message, the KSS conducts precise frequency tuning! and synchronization. Fine tuning is completed at the IF level with the help of a phase accumulator circuit in the ECHOO5 OPE modem circuit (Fig. 3), shown in detail in Fig. 6. The frequencies of the IF range are formed by the repeated accumulation (with the frequency of the digital reference generator of the IF synchronous pulses) of a number that represents the jump of the phases in the phase accumulator. The U5R/MOM modem processor through the O5R/MOM data bus (Fig. 3) first outputs a 24-bit number E to the Kx BOB circuit, because the number is connected (as will be described further) to the required IF necessary for demodulation of a specific incoming signal according to the principle " interval by interval". The 24-bit number GE is loaded into one of the four registers K16 - K46 in the left side of Fig. 6. In an illustrative version, in 7/0 Kotor used a 16-bit processor, a 24-bit number of frequencies! E is presented in 16-bit and 8-bit segments, however, to simplify the figure, it is shown that a 24-bit number is included in a composite 24-bit register. Each of the registers K16 - K46 is intended for one of the reception time intervals. Since

The KSS message is expected in the first Kx time interval, a 24-bit number is loaded into the corresponding one of the four registers K16 - K46, for example, into the K16 register. With a corresponding /5 circle for the first Kx time interval, the contents of the K16 register are provided to the synchronization register 602, the output signal of which is then fed to the upper input of the adder 604. The input of the adder 604 is connected to the input of the storage register 606.

The lower input of adder 604 receives the output signal of register 606. Register 606 is synchronized by a 21.76MHz BO5 generator of sync pulses, and its content, accordingly, periodically returns to adder 604.

Periodic re-submission of the contents of the register 606 to the adder 604 causes the adder 604 to count from the number of EPs originally received from the K16 register. In the end, the adder 606 reaches the maximum number that it can support, then it overloads, and the count resumes again with a low final value. This gives the effect of multiplying the frequency of the ОО5 master generator by a fractional value so that the received IF signal of the local generator (heterodyne) has the same frequency multiplied by the fraction, with a dust-like signal form. Since the register 606 i) is a 24-bit register, 24 it overflows when its content reaches 2. 27. Therefore, the register 606 effectively divides the frequency 005 of the synchronizer 227 by 2 and simultaneously multiplies it by R. This circuit is called a phase accumulator, because . the current output number in register 606 indicates the current phase frequency "(about the IF range.

The accumulated phase from the register 606 is fed into the sinusoidal signal approximation circuit 622, which is more fully described in US Patent No. 5,008,900, on "Subscriber Unit for Digital Systems! Radio Communications with Subscribers". Circuit 622 converts the dusty signal of register 606 into a sinusoidal form. The input signal of the circuit 622 is resynchronized by the register 624 and then fed to one of the inputs of the filter and the noise generator 632. The output signal of the filter 632 is fed to the second input of the adder 634. The output "I" of the adder 634 is connected to the data input of the filter 632 and to the input of the resynchronization register 636. This variable-coefficient noise shaper filter 632 is more fully described in US Pat. No. 5,008,900.

The characteristics of the noise generator are adjusted according to the "interval by interval" principle using the 7-bit noise generator control field, which is combined with the least significant byte of the frequency reference field obtained from the OBR/MOM bus. - c The noise shaper can be enabled or disabled, up to 16 filter coefficients can be selected, rounding can be enabled or disabled, and the feedback characteristics of the noise shaper can be changed to enable the use of the 8-bit DAC output (as shown in Fig. 6) or a 10-bit DAC output (not shown) by using appropriate fields in the noise generator control field for each interval, in four registers KM16 - KM46. The multiplexer t» МРХбЕ selects one of the four registers KM16 - KM46 for each time interval, and the received information is re-synchronized by the register 630 and output to the control input of the filter of the noise generator 632. (95) Fig. 7, - SHOE - Digital modulation of IF signals t 50 The exact value of the IF for any of the transmission channels is generated according to the "interval by interval" principle by the THO IE scheme in the OOE block of the modem (Fig. 3), which is shown in detail in FIG. 7. According to the "interval by 4) interval" RGIK filter of the transmission channel (not shown) forms a stream of data complex (I, C) information signal (1bkilosymbols/s), received from the OBR modem, which will modulate each of the generated intermediate frequencies. This stream of information data can be formed in such a way that it can be transmitted in a limited range of operating frequencies allocated for the corresponding RUCH channel. The initial processing of this information signal includes the formation of pulses with a finite impulse response to reduce the frequency range to 17-10kHz. Such a transformation of pulses forms an in-phase and quadrature component! for use in IF modulation. 60 After forming the pulses, several steps of linear interpolation are used. The initial interpolation is performed to increase the sampling frequency of the modulating signal, subsequent additional interpolations ultimately increase the sampling frequency and increase the frequency at which the main spectral responses occur, up to 21.76 MHz. Suitable methods of interpolation are described, for example, in the book "Miyiga(e Ridna! Zidpa! Rgosezvipd" Stospiege apa Karbipeg, Rhepiise-Nai! 1993. 65 In-phase and quadrature components of the formed and interpolated modulating signal are fed to the I and OO inputs of the mixers МХ1 and МХО modulator parts of the scheme shown in Fig. 7.

On the left side in Fig. 7 shows the scheme of digital generation of the transmitted IF. The exact generated frequency is determined when the base station informs the SS cluster controller (Fig. 1), which number of the interval and RF channel is assigned to the time interval serving the specific conversation. A 24-bit number that identifies a specific IF with a high degree of resolution (for example, t/-1.3Hz) is provided by the OZR/MOM processor (Fig. 3) through the data OBR/MOM bus. Ztot 24-bit frequency counter! is registered in the corresponding one of the 24-bit registers K17-K47. Each of the registers

K17-K47 is intended for a specific one of the four Th-time intervals.

A time interval counter (not shown) generates a number of repeating two-bit time 7/0 intervals obtained from the synchronization signals received through the backplane as described earlier. The time interval counting signal occurs every 11.25 ms, regardless of whether the same time interval is used for modulation of ORBK, ORBZK or 16P5K. When the time interval for which this frequency will be fixed is reached by the time interval counter, the time interval count selects the corresponding one of the K17-47 registers, using the MPX71 multiplexers, to feed 7/5 of its contents to the resynchronization register 702 and finally to the upper input of adder 704.

Thus, the second (or the same) IF in the form of a 24-bit reference (can be used for each consecutive time interval. This 24-bit frequency reference! is used as a phase jump for ordinary circuits! phase accumulator containing adder 704 and register 706. The complex carrier is generated by converting the accumulated phase information of the dust form in register 706 into a sinusoidal and cosine signal using cosine approximation circuits 708 and sinusoidal approximation circuits 722. These circuits 708 and 722 are described in detail in US Pat. No. 5 008 900. The output signals of circuits 708 and 722 are resynchronized by registers 710 and 724, respectively, and fed to mixers 712 and 714, respectively. The output signals of mixers 712 and 714 are fed to resynchronization registers 714 and 728, respectively. with the adder 716, they form a general complex (I, C) modulator. The input signal is mmator 716 is combined with a cosine reference

IF with a multiplexer 718, which is controlled by the signal of the SMU MOOE from the internal register (not shown) and) the OORAZIS 450 scheme (Fig. 3). The input signal of the multiplexer 718 is re-synchronized by the register 720, the input of which is connected to a noise generator with variable coefficients, as described with links in Fig. 6, consisting of adder 734 and filter 732, with associated control registers Ge

EM17 - KM47, control multiplexer MPX76 and resynchronization registers 730 and 736.

The noise generator compensates for quantization noise due to the final resolution of the digital-to-analog conversion. Because of the noise! quantization of distributions! evenly, their spectral characteristics are apparently similar! with white Gaussian noise. The noise power that falls within the bandwidth of the transmitted signal, which is relatively narrow compared to the sampling frequency, can be reduced in the same proportion as the desired bandwidth! refers to the sampling frequency. For example, if the modulating signal has a bandwidth of 20 kHz, and the sampling frequency is 20 MHz, then the improvement in the signal-to-noise ratio is 10001, or baud. The characteristics of the noise generator are regulated on the "interval by interval" principle by the 7-bit control field of the noise generator, as described in connection with Fig. 6. "

Fig. 8 - Generation of synchronous pulse systems! An important aspect of our invention is that the quality of the thing is preserved, despite the physical spatial separation of the base station and the remote cluster. Changes in timing between;" base station and cluster, as well as changes in the timing of the decoded and encoded speech signals will lead to various forms of speech quality deterioration, which can be heard in the form of extraneous clicks and crackling in the speech signal. According to the invention, the strict congruence of 5" timing is guaranteed by the synchronization of all timing signals, in particular, the signals used for ADC synchronization, speech codecs on modules 101 - 108 of the quadrilateral lines, as well as the PCM 200 and 500 tracts, relative to the direct radio channel. As shown in Fig. 8, the main sync pulse, 2) used in this system, is obtained with the help of a generator with a frequency of 21.76 MHz (not shown), which outputs its signal, as shown on the left side of Fig. 8. Ztot signal frequency! 21.76MHz is used to synchronize the sample synchronizer with a frequency of b4kHz with the symbol transition time in the received

F radio signal. More specifically, the frequency signal! 21.76 MHz is first divided by 6.8 with the help of schemes! of the fractional frequency divider of the synchronizer 802, which performs this fractional division by dividing the synchronizing pulse of 21.76 MHz by 5 different coefficients in a repeating sequence of 6, 8, 6, 8, 6 seconds to obtain a synchronizing pulse with an average frequency of 3.2 MHz.

The programmable dividing device of the synchronizer 806 is a dividing device (F, ordinary type) and is used to divide the 3.2 MHz sync pulse with the help of a divider, the exact value of which is determined by OZRM. Generally, the programmable dividing device of the synchronizer 806 uses a divider 50 to obtain a sample synchronization signal with a frequency of 4 kHz at its output. The output signal of the sample synchronizer with a frequency of 64 kHz of the dividing device 806 is used for gating the ADC 804 of the receiving channel (also shown in Fig. 3). The ADC 804 converts the received samples

IF in digital form for use by the O5R/MOM processor.

In Fig. 8, the OBR/MOM M processor acts as a phase/frequency comparator to calculate the phase error in the received symbols from their ideal phase values using a 65 b4kHz clock signal to determine the moments when the phase error is measured. The O5R/MOM processor determines the input signal of the fractional correction of the timing of the system. Ego is fed into a programmable dividing device

806 to determine the coefficient of division. If the clock frequency signal! b4kHz has a frequency slightly higher than the frequency of the initial phase of the symbols in the received intermediate frequency signal, then the OBR/MOM processor eats a fractional timing correction, which temporarily increases the divisor of the dividing device 806, thus lengthening the phase and lowering the average frequency of the output signal of the clock signal frequency! 64 kHz of the dividing device 806. Similarly, if the frequency of the clock signal b4 kHz is lower than the phase transition frequency of the received symbols, then the divider of the dividing device 806 is briefly reduced.

The clock signal of discretization with a frequency of b4kHz bypasses the programmable dividing 7/0 synchronizing device 806 and is multiplied by the frequency by a multiplier of 64 using ordinary circuits! analog multiplier of phase automatic frequency adjustment 808 to obtain a sync signal with a frequency of 4.096 MHz. Sync frequency! 4.096 MHz is delivered to time slot switches 310 and 320 (see Fig. 1), which divide the 4.096 MHz clock signal by 2, forming two 2.048 MHz clock signals, which are used by speech codecs on line modules 101 - 108 (Fig. 1) for sampling and conversion of /5 analog speech input signals into MKM-speech signal. Providing a commonly received sync pulse of 2.048MHz for vocodecs, which is in sync with the radio-generated sync pulse of b4kHz sampling, guarantees that there will be no slippage of cycles between the two sync signals. As mentioned, such slippages in other cases would lead to audible deterioration of voice quality, perceived as clicks and crackles in the speech signal.

The above describes an illustrative version of the invention. Another option! can be created by specialists in this field without departing from the essence and scope of the invention. Among such options, for example, there was an increase in the sampling speed on PCM-buses to create the possibility of processing as

PC-speech and transmitted signals on the same switch of time intervals without deterioration of the quality of PC-speech coding. In addition, the circuit for generating transmitted pulses of the ABIS (specialized IC) can be modified to ensure the use of other forms of modulation than FM modulation, such as quadrature amplitude modulation and frequency modulation. It should be kept in mind i) that although the illustrative version describes the use of a common pool of modems with fast frequency adjustment for group service! remote subscriber points in a modular cluster, a similar group of modems with fast frequency adjustment! can be used at a base station to maintain communication between such a cluster and any number of remote subscriber points. Finally, a different transmission medium than radio can be used, for example, a coaxial transmission line or a transmission line with the use of a fiber optic cable.

IS)

Claims (26)

The formula of the invention 1. A radiotelephone system containing a base station and a plurality of remote subscriber points, in which a repeating group of time slots maintains radio communication between specified subscriber points and a specified base station, and messages are received and transmitted by each "subscriber point" through a duplexer connected to a converter, characterized by that 73 specified subscriber point includes a group of modems connected to its converter to support numerous two-way messages, each of specified modems provides digital synthesis of any of a plurality of channel-identifying frequencies at successive time intervals, and has a cluster controller connected to Kk specified modems and specified converter, as well as connected to multiple subscriber lines in such a way that the specified cluster controller selectively provides specified modems to maintain communication between subscriber lines we points and specified base station at consecutive time intervals. o 2. A radiotelephone system containing a base station, a set of remote subscriber points, 5r at which the base station is designed to determine a repeating group of time intervals for maintaining radio communication between specified subscriber points and the specified base station, and F messages are received and transmitted by each subscriber point through duplexer connected to a converter, characterized in that said remote subscriber point includes a group of modems connected to its converter to support multiple bidirectional messages, each of said modems provides digital synthesis of any of a plurality of channel-identifying frequencies at successive time intervals, and has the cluster controller, (F) connected to the specified modems and the specified converter, as well as connected to a plurality of GI subscriber lines in such a way that the specified cluster controller selectively provides the number of specified modems to maintain communication between the specified subscriber points and the specified base station at successive time intervals simultaneously on different frequencies identifying the channel. C. The radiotelephone system according to claim 2, characterized by the fact that the specified cluster controller provides the entire specified group of time slots to one of the specified modems before providing the time slot to any of the remaining modems. 65 4. Radiotelephone system according to claim 3, characterized by the fact that the rest of the modems are in a state of reduced power until they are provided with a time interval specified by the cluster controller. 5. Radiotelephone system according to claim 2, characterized by the fact that the specified cluster controller includes means for synchronizing modems with the specified base station. 6. Radiotelephone system according to claim 5, characterized by the fact that the specified means for synchronization includes a means for sequential transmission of commands to one or more modems from a set of modems to conduct a search among the specified frequencies identifying the channel during one of the time intervals. 7. The radiotelephone system according to claim 3, characterized by the fact that one of the modems provided by the 7/0 cluster controller provides synchronization information to the rest of the modem!. 8. The radiotelephone system according to claim 7, characterized by the fact that one or more specified modems calculate the corresponding set of synchronization parameters, and the cluster controller determines the reliability of the corresponding sets of synchronization parameters, and the cluster controller identifies one of the modems to deliver synchronization information to the other modems. 9. Radiotelephone system according to claim 2, characterized by the fact that the remote subscriber point additionally contains a converter with a frequency increase! for converting a set of channel-identifying frequencies into a radio frequency range. 10. Radiotelephone system according to claim 2, characterized by the fact that it additionally contains a converter with a frequency reduction! for the conversion of radio frequency range signals received by the base station into a set of intermediate frequencies identifying the channel. 11. The method of work! a cluster of subscriber line circuits served by a set of modems that have access to any of a set of frequencies identifying the channel during a group of repeating time intervals, which minimizes the synchronization delay and consumed power, characterized by the fact that c a) synchronize the first of the indicated modems with one specified time interval groups, b) distribute synchronization from the specified first of the modems to the rest of the modems with the indication i) one time slot, c) provide the channel identification frequency to the specified group of time slots used by the specified first of the modems, before providing the corresponding slot ("9 with the remaining modems from many modems. 12. A radiotelephone system, including a central telephone base station and a plurality of remote subscriber points, in which a repeating group of time intervals is maintained by radio communication between specified subscriber points and the specified central telephone base station, and messages are received and transmitted by each subscriber point through a duplexer, connected (M z5 Kk to the converter, characterized by the fact that the specified subscriber point includes a modem, "connected to its converter to support numerous bidirectional messages, and the specified modem provides digital synthesis of any of the set of frequencies identifying the channel, and has a cluster controller connected to the specified modem and the specified converter, and such a connection to a set of subscriber lines in such a way that the specified cluster controller collectively provides the specified modem with any of the specified frequencies in sequence x time intervals) with intervals. . 13. A radiotelephone system, including a central telephone base station and a set of remote subscriber points, in which a given number of repeating time intervals supports radio communication between specified subscriber points and the specified central telephone station, characterized by the fact that the specified subscriber point contains a group of modems, each of which i" provides a digital synthesis of any of the set of channel-identifying frequencies, and the cluster controller to provide each of the specified modems with the number of channel-identifying frequencies equal to the specified number of time intervals to support communication between the specified subscriber points and with the specified central telephone exchange at successive time intervals. 14. The method of providing a repeating group of time intervals to a plurality of telephone calls in a radiotelephone system having a central telephone base station and a set of remote F subscriber points, in which the repeating group of time intervals supports radiotelephone calls between specified subscriber points and a specified central telephone station, a group of modems, each of which is capable of processing a specified set of telephone calls at successive time intervals, which is distinguished by the fact that a) they determine which modem is active! have a free time interval, (F, b) give preference ratings to the specified free time intervals in the specified group of modems, c) determine which of the specified time intervals has the highest preference among the indicated ratings, d) provide the time interval corresponding to the specified specified highest to the assessment of preferences, following from the visa instructions. 15. A radiotelephone system containing a base station and a plurality of remote subscriber points, in which a repeating group of time slots supports radio communication between specified 65 subscriber points and the specified base station, and messages are received and transmitted by each subscriber point through a duplexer connected to a converter, characterized by that said base station includes a group of modems connected to its converter to support multiple bidirectional messages, each of said modems provides digital synthesis of any of a plurality of channel-identifying frequencies at successive time intervals, and has a cluster controller connected to said modems and said converter , as well as the connection of multiple subscriber lines in such a way that the specified cluster controller selectively provides a modem indication to maintain communication between the specified subscriber points we and the specified base station at successive time intervals. 16. A radiotelephone system containing a base station, a set of remote subscriber points, 7/0, while the base station is designed to determine repeating groups! time intervals for maintaining radio communication between the specified subscriber points and the specified base station, and messages are received and transmitted by each subscriber point through a duplexer connected to the converter, characterized by the fact that the specified base station includes a group of modems connected to the converter to support multiple bidirectional messages , each /5 of the specified modems provides digital synthesis of any of a plurality of channel-identifying frequencies at successive time intervals, and has a cluster controller connected to the specified modems and the specified converter, as well as connected to a plurality of subscriber lines in such a way that the specified cluster controller selectively provides any of the specified modems for maintaining communication between the specified subscriber points and the specified base station at 2 consecutive time intervals simultaneously on different identifying channels l frequencies. 17. Radiotelephone system according to claim 16, characterized by the fact that the specified cluster controller provides the entire specified group of time slots to one of the specified modems before providing the time slot to any of the remaining modems. 18. The radiotelephone system according to claim 17, characterized by the fact that the rest of the modems are in s 2g5 of constant reduced power until they are provided with a time interval indicated by the cluster controller. 19. Radiotelephone system according to claim 16, characterized by the fact that the specified cluster controller includes means for synchronizing the specified modems with the specified subscriber point. 20. Radiotelephone system according to claim 19, characterized by the fact that the specified means for synchronizing Gezo includes a means for sequential transmission of commands to some of the specified set of modems for conducting a search among specified xx identifying channel frequencies during one of the specified time intervals. co 21. The radiotelephone system according to claim 17, characterized by the fact that the specified one of the specified modems, provided by the cluster controller, provides information about the synchronization of the remaining specified 5 Modems. "Mr 22. The radiotelephone system according to claim 21, characterized by the fact that one or more specified modems calculate the corresponding set of synchronization parameters, and the cluster controller determines the reliability of the specified corresponding sets of synchronization parameters, and this cluster controller identifies the specified one of the specified modems to deliver synchronization information to the others !m « modems. shsh c 23. The radiotelephone system according to claim 16, characterized by the fact that the remote subscriber point additionally contains a converter with a frequency increase for multiple conversion;" identifying channel frequencies in the radio frequency range. 24. The radiotelephone system according to claim 16, characterized by the fact that it additionally contains a converter with a frequency reduction for converting signals of the radio frequency range received from the indicated 5" subscriber point into a set of intermediate frequencies identifying the channel. 25. A radiotelephone system, including a base station and a set of remote subscriber points, in which a repeating group of time intervals maintains radio communication between the subscriber points and the indicated base station, and messages are received and transmitted by each subscriber point through a duplexer connected to a converter, characterized by the fact that said base station includes a modem connected to its converter to support F multiple bidirectional messages, and said modem provides digital synthesis of any of a plurality of channel-identifying frequencies, and has a cluster controller connected to said modem and said converter, and also connected to multiple subscriber lines in such a way that the specified cluster controller selectively provides the specified modem with any of the specified frequencies at successive time intervals. (F, 26. Radiotelephone system, including a base station and a set of remote subscriber points, in which a given number of repeating time intervals support radio communication between the specified subscriber points and the specified base station, characterized by the fact that the specified base station contains a group of modems, each of which provides a digital synthesis of any of the plurality of channel-identifying frequencies, and has a cluster controller for providing each of the specified modems with an amount of the specified channel-identifying frequencies equal to the specified number of specified time intervals for maintaining communication between the specified subscriber points and the specified base station at successive time intervals. b5